What About Bob?

Dr. Leo Marvin is a successful therapist with a best-selling book out and a gig with a morning show scheduled. He is also very arrogant.

He takes on one appointment with a patient, Bob, who has been jumping and transferred from psychiatrist to psychiatrist. Bob has pantophobia - he's afraid of everything. Dr. Marvin encourages a first-name basis, as psychiatrists do, and recommends his book to Bob.

Bob starts hero-worshipping Dr. Marvin immediately. Unfortunately for him, Dr. Marvin is going on vacation to his vacation house and does not want to deal with clingy patients. It's a family vacation for a seriously messed-up family.

Unfortunately for Dr. Marvin, Bob is not going to give up that easy. On learning what town Dr. Marvin is vacationing in, he takes the bus there, bringing just the essentials and his goldfish. The locals disapprove of Dr. Marvin, so they're happy to help Bob visit him.

When Dr. Marvin's family meets Bob, they are won over by him. Bob almost accidentally helps everyone with their problems, except Dr. Marvin, of course, whom he is unwittingly driving over the edge...

Tropes used in What About Bob? include:

All Psychology Is Freudian: To the point where Dr. Marvin named his son Sigmund and his daughter Anna (the name of one of Freud's daughters and the one to follow him into psychoanalysis).
Angrish: It's supposed to be "Get out of the car!", but...
Break the Haughty
Busman's Holiday
The Cat Came Back: No matter what Leo does, Bob manages to come back which makes Leo's sanity slip more.
The Cobbler's Children Have No Shoes
The Complainer Is Always Wrong: Dr. Marvin
Critical Psychoanalysis Failure
Dr. Jerk: Dr. Marvin is this the entire movie.
Dysfunction Junction
Epiphanic Prison
Everything's Better with Bob
Hourglass Plot: By the end of the movie, Bob is cured of his pantophobia, and Leo is driven insane and catatonic.
Inevitable Waterfall
Insult Backfire: All of Leo's insults, threats and, eventually, murder attempts are like water off Bob's back, as Bob is convinced that it's all merely part of the therapy. Indeed, throughout the movie he has nothing less than the utmost respect for Leo.
Laser-Guided Karma: Given that Leo is a Dr. Jerk and Bob is actually a little innocent when you consider that he doesn't mean to drive people nuts with his neurosis, the whole movie is just the universe evening things out for Bob by letting Leo's previous behavior and treatment towards his family and other people come back to bite him in the ass. Literally, as things got better for Bob they got worse for Leo.
Leno Device
Living Shadow: Used in the poster art.
Loony Fan: Bob was recommended by his last therapist to Dr. Marvin. Bob takes a liking to Leo to the latter's chagrin.
The Messiah: Bob, who's also a kind of holy Fool.
Only Sane Man: Leo is the only one to notice Bob's obvious insanity, instability, and inappropriateness. All the supposedly normal people side with Bob against him. Although it kind of helps that Bob, while clearly not very well adjusted, is ultimately pleasant, friendly, well-meaning and easy-to-like, while Leo is an arrogant, distant and thoughtless tool even before Bob enters his life.
- This is gradually inverted as the movie goes on, with Leo becoming more unstable as Bob begins to get better.
Parental Neglect: The fact that Leo's kids (and wife) actually got along better with the neurotic and phobic Bob, who had driven previous psychiatrists insane, should say something about how Leo has treated his family.
The Red Stapler: Bob's turquoise and yellow "Don't Hassle Me I'm Local" T Shirt
Sanity Slippage: Leo suffers this the more Bob gets involved with his family.
Sink or Swim Mentor: Leo unwittingly and unwillingly becomes this for Bob -- the more desperate his attempts to get rid of Bob become, the more Bob assumes that this is all part of the therapy, and the more Bob ends up being helped by it, to the point Leo unwittingly helps Bob become a healthy and functioning person.
Speak Now or Forever Hold Your Peace: Leo breaks out of his catatonia during the wedding of his sister and Bob, letting out a Big No when the vows are made.
Stuff Blowing Up: What "Death Therapy" was meant to be. Bob brought the explosives into the house after he got out of the bindings Leo had set tied him with.
Survival Mantra: "Baby steps..."
Tempting Fate: Siggy asks the catatonic Leo "What's the worst that could happen?" before the film cuts to Bob and Leo's sister's wedding.
Title Drop: Done a couple of times.
Tourette's Shitcock Syndrome
Why Do You Hate the Dog?: The Ur-example.
Vitriolic Best Buds: Bob and Leo. At the end Bob becomes his brother-in-law.